Airplane propeller



July 28, 1931. H. H. HARDIN 1,816,730

IRPLANE PROPELLER Filed June 1o, 19:50

muuu /4 Frgl- Patented July 28, 1931 UNITED'ISTATES PATENT oFFlcl-zHARVEY H. HARDIN, F MAITLAND, MISSOURI, ASSIGr'NOR OF ONE-HALF T0 G.HILSABECK, OF GRAHAM, MISSOURI l AIRPLANE PROIPELLER Application led.Tune 10,

This invention relates to reversible prof pellers and an object of theinvention is to provide a propeller blade in which the pitch of theblades may be changed easily and quickly by the operator.

A further object is to provide an adjustable propeller withoutcomplicated gearing, racks or pinions.

A further general object therefore is to provide a new and improvedApropeller which may be simply, yet reliably adjusted.

Other objects and advantages will become .apparent as the descriptionproceeds.

Referring to the accompanying drawings, which are made a part hereof andon which similar reference characters indicate similar parts,

Flgure l is a side View partly in section of the device of my invention,

Figure 2 a plan view of the same,

Figure 3 an end view of the propeller as shown in Figure 2, looking fromthe rightand being on a reduced scale, and

Figure 4 a diagrammatic illustration of the several positions taken bythe propeller during adjustment.

In the drawings numeral indicates the drive shaft from the engine uponwhich shaft the propeller is mounted. This pro, peller consists of asleeve 11 which is mounted on the drive shaft 10 and keyed thereto torotate with the shaft. The forward end of the sleeve 11 is provided witha pair of integral Hange's 12. Propeller blades 13 and 14 are securedupon the flanges 12 by means of lugs 43 andlpins or bolts 15 and 16about which latter they are Aadjustable on the flanges. Meansfor-clausing this adjustment is as follows:

The blades preferably have at their inner ends flanged hubs 18 and 19,these hubs each being provided with lugs 20 and 21. Neatly fitting -butaxially sliding uponthe sleeve 11 is'a collar 22. This collar has anannular groove 23 `which forms the inside 1930. Serial No. 460,251.

' This ring is provided with short stub spin-` dles 31 and 32 atopposite sides to which are attached the ends 33 and 34 of an operatinglever 35.

As previously described the propeller blades are pivoted on pins 16 and17. As shown in Figure 2 and' shown .diagramlmatically in Figure 4 thesepins are eccentric with respect to the axis of the blades. When thepropeller blades are moved on these pivoted pins therefore they do notrotate in a complete circle or the arc of a complete circle but ratherthe axis of the blade will move about the pivots 16 and 17. As shown inFigure 2, for example, when this propeller is adjusted on its center 17the axis of the blade indicated at 36 will move in an arc having 17 asits center. When the adjusting lever 35 is pushed for- Ward thepropeller 13 will lie sul/tantially in the line 37-38 shown in FigureWhen the adjusting lever is moved to the left, the face of the propellermay assume the position shown in lines 39-40 -1 of Fig'. 4. Line 41-42indicates a position intermediate the twopositions just mentioned. A, Band C .indicate the -axis of the main drive shaft 10, the pivot point ofthe blades and the axis of the propellerl blades, respectively.

From the foregoing description the operation of my device should be .aparent.

Just a Word concerning the ev ect created by the adjustment should begiven. At nor- -mal atmospheric pressure and in a relatively calm Windthe propeller blades will be set at a pitch which has been predetermined,by the engineer. At normal speeds this will be theppitchwhich will givethe best possible ERNEST 'ullingeiectby the engine. At high speeds,combination with a propeller shaft of a owever, this given pltch of theblade will sleeve having. opposite integral vflanges not roduce thehighest eiiiciency on the part thereon, propeller blades havlng integralof t e engine. During flight. the blades of hubs pivoted on saidflanges, sa1d blades 5 an engine travel in a spiral. At high speedsbeing pivoted eccentric of their axes, lugs 70 with the' blades havingthe same pitch as on said blades, links to pivot the blades, they had atlow speeds there will be a the axes of the blades moving about the lostmotion of the blade., At suchhigh pivot point, substantially as setforthf speeds therefore it is desirable that the pitch In witnesswhereof, I have hereunto set of the blade be increased soas to create myhand at Washington, District of Colum- 75 the proper push or pull`againstthe air. bia, this tenth vday of June,l A. D. nineteen Not only'is this necessary at high's'peeds hundred and thifrt-.

but it is necessary in different wind ve- RVEY H. 'BARBIN'.

locities, for the same effect is present when f going against the windas is found in ily-v f 80 ing at very high speeds. It is necessary totilt the bladesto correspond to thevelocity of the wind in order' torealize the highest eiiidiency on -the part of the engine. The

density of the air is another factor'to be ss taken into account. Thedensity of the atmosphere at sea level is' uite different `from that atan elevation o several thousand feet and at high altitudes the airbecomes very rare. When flying at high altitudes 90 therefore it becomesnecessary to tilt the blades again in order to enable them to operate ata maximum pulling eiii'cieney. By the use of my invention adjustment forall of these occaslons may be instantly made. v 95 With adjustingmechanismior propeller -blades nowl in use gears, pinions and racks areused; while. these may, be sufliciently v reliable for marine pro ellerblades they are entirely tool hazardous or airplane construc- 100 tionsince theyr easily get out of order. W ith my construction there are nogears to get out 'of'o'rder and 'all of the parts may be rigidly andthus reliably secured together with rela- ,Q40 tively little dan erloftheir breaking or 105 getting out of or er. j I

It will be obvious to those skilled in the artthat various changes ma bemade in mfy'devicek without departing rom the spirit o the invention,and therefore I do not 110 `limit myself to what is shown in thedrawings and described in the specification, but

onl as indicated b the ap nded claims. s aving `thus fully descri ed msaid in- 60' vention,l what I claim'as new an desire to 115 secure byLetters Patent, is:

1. A reversible propeller comprising the Acombination with .a propellershaft of a sleeve vmounted thereon and rotatable there-1 'v with, theforward end of the sleeve being 120 eller blades pivotally` attached tosaid anges, said blades being pivoted at oints provided with opposite.lintegral flanges, pro-` "ntricgof thir axes, a collar slida leon id.sleeve, r a in uredy@j axially therewith but to ,th collar, and linconnecting vrs'on said Propeller bladesg/ prgpgller comprising the Y 130g within said collar and -125,

